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From: Thomas Gleixner <tglx@linutronix.de>
To: Alexey Dobriyan <adobriyan@gmail.com>, x86@kernel.org
Cc: mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
	hpa@zytor.com, linux-kernel@vger.kernel.org, adobriyan@gmail.com
Subject: Re: [PATCH 1/5] x86/alternative: simplify DUMP_BYTES macro
Date: Tue, 05 Apr 2022 18:36:53 +0200	[thread overview]
Message-ID: <87v8vn1o7u.ffs@tglx> (raw)
In-Reply-To: <20220311144312.88466-1-adobriyan@gmail.com>

On Fri, Mar 11 2022 at 17:43, Alexey Dobriyan wrote:
> Avoid zero length check with clever whitespace placement in the format
> string.
>
> Signed-off-by: Alexey Dobriyan (CloudLinux) <adobriyan@gmail.com>
> ---
>  arch/x86/kernel/alternative.c | 21 +++++++++------------
>  1 file changed, 9 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index 5007c3ffe96f..6c9758ee6810 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -66,13 +66,10 @@ do {									\
>  	if (unlikely(debug_alternative)) {				\
>  		int j;							\
>  									\
> -		if (!(len))						\
> -			break;						\
> -									\

How does that clever whitespace placement prevent this being printed in
the len == 0 case, which is a legit case?

>  		printk(KERN_DEBUG pr_fmt(fmt), ##args);			\

This is debug muck. So why does it have to be "optimized"?

Thanks,

        tglx

      parent reply	other threads:[~2022-04-05 21:50 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-11 14:43 Alexey Dobriyan
2022-03-11 14:43 ` [PATCH 2/5] x86/alternative: bump MAX_PATCH_LEN Alexey Dobriyan
2022-03-11 14:43 ` [PATCH 3/5] x86/alternative: record .altinstructions section entity size Alexey Dobriyan
2022-03-12 21:17   ` Peter Zijlstra
2022-03-13 18:05     ` Alexey Dobriyan
2022-04-05 19:24       ` Thomas Gleixner
2022-04-06  8:30         ` Rasmus Villemoes
2022-03-11 14:43 ` [PATCH 4/5] x86/alternative: make .altinstr_replacement section non-executable Alexey Dobriyan
2022-03-12 15:31   ` Peter Zijlstra
2022-03-11 14:43 ` [PATCH 5/5] x86/unwind/orc: delete dead write in __orc_find() Alexey Dobriyan
2022-03-11 15:13   ` David Laight
2022-03-11 16:59     ` Alexey Dobriyan
2022-03-12 16:36 ` [PATCH 1/5] x86/alternative: simplify DUMP_BYTES macro Joe Perches
2022-03-13  0:14   ` Joe Perches
2022-03-13 18:09   ` Alexey Dobriyan
2022-03-14  3:21     ` Joe Perches
2022-04-03 22:25 ` Borislav Petkov
2022-04-05 16:36 ` Thomas Gleixner [this message]

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